1. Field of the Invention
This invention relates to the field of radiography and more specifically to lead foil screens used to intensify images produced using industrial radiography. Still more particularly, this invention relates to an improved lead screens used with photographic elements associated therewith
2. Discussion of the Prior Art
Industrial radiography is a system used to determine whether or not defects might exist in large, dense items such as the girders of bridges or the fuselages of aircraft, for example. This system is also used to determine defects within smaller items which cannot be visually inspected. Conventionally, a special photographic film is placed near the device to be radiographed, and X-radiation is applied thereto. Even though photographic, radiographic elements are not particularly sensitive to X-rays, large doses of these X-rays can be applied since they will not harm the items being examined in this manner. The use of lead screens and foils in conjunction with industrial, radiographic photographic elements to produce quality images, is well-known. These screens are conventionally comprised of a lead coating on paper or cardboard. These screens serve to intensify the radiographic image somewhat and find great utility within the described system. Flexibility is important within this system since it is sometimes necessary to wrap the film and screen around the item to be radiographed in order to obtain an image of the entire interior thereof. In a copending application, Robinette, U.S. Ser. No. 07/398.104, filed 08/24/89, the subject of which is incorporated herein by reference, there is described a flexible lead or lead oxide absorbing screen for X-ray photography comprising a flexible, polymeric support, an adhesive layer, a layer of lead or lead oxide dispersed in a binder and coated over said adhesive layer, and an overcoat layer. These flexible screens are much improved over the conventional paper or cardboard support used by the prior art and do not absorb moisture which can adversely affect the photographic emulsion associated therewith. Additionally, these flexible screens have excellent film/screen contact which improves the images produced when the screens are exposed conventionally with a photographic emulsion containing element, for example. Also, the flexible screens do not tend to absorb X-radiation, a process which interferes with the production of an X-ray image on the photographic film. However, these flexible screens produced on polymeric supports tend to produce unwanted electrostatic changes during normal use.